Evaluation of a portable image overlay projector for the visualisation of surgical navigation data: phantom studies

Abstract

Introduction Presenting visual feedback for image-guided surgery on a monitor requires the surgeon to perform timeconsuming comparisons and diversion of sight and attention away from the patient. Deficiencies in previously developed augmented reality systems for image-guided surgery have, however, prevented the general acceptance of any one technique as a viable alternative to monitor displays. This work presents an evaluation of the feasibility and versatility of a novel augmented reality approach for the visualisation of surgical planning and navigation data. The approach, which utilises a portable image overlay device, was evaluated during integration into existing surgical navigation systems and during application within simulated navigated surgery scenarios. Methods A range of anatomical models, surgical planning data and guidance information taken from liver surgery, cranio-maxillofacial surgery, orthopaedic surgery and biopsy were displayed on patient-specific phantoms, directly on to the patient's skin and on to cadaver tissue. The feasibility of employing the proposed augmented reality visualisation approach in each of the four tested clinical applications was qualitatively assessed for usability, visibility, workspace, line of sight and obtrusiveness. Results The visualisation approach was found to assist in spatial understanding and reduced the need for sight diversion throughout the simulated surgical procedures. The approach enabled structures to be identified and targeted quickly and intuitively. All validated augmented reality scenes were easily visible and were implemented with minimal overhead. The device showed sufficient workspace for each of the presented applications, and the approach was minimally intrusiveness to the surgical scene. Conclusion The presented visualisation approach proved to be versatile and applicable to a range of image-guided surgery applications, overcoming many of the deficiencies of previously described AR approaches. The approach presents an initial step towards a widely accepted alternative to monitor displays for the visualisation of surgical navigation data.

Validity of the international physical activity questionnaire short form (IPAQ-SF): A systematic review

“…Several routine instruments are available to measure physical activity, including self-report questionnaires, indirect calorimetry, direct observation, heart rate telemetry, and movement sensors [5]. All of these methods have well-known limitations [6], and for physical activity there is currently no perfect gold-standard criterion [7,8]. Movement sensors such as accelerometers have grown in popularity recently as a measure of physical activity [9], not only due to their objective measurements, but also due to their relatively small and unobtrusive size.…”

Improved Screw Placement for Slipped Capital Femoral Epiphysis (SCFE) Using Robotically-Assisted Drill Guidance

“…In addition to image-guided navigation techniques, other methods have been investigated, either to augment the available visual information or to provide additional guidance to a conventional surgical approach. An infrared system was used to track the surgical tool position and provide depth guidance during drilling [7]. Simpler mechanical frames, in the form of a physical stopper, depth guide and depth guidance rings have been implemented to constrain the drill depth.…”

Performance of the international physical activity questionnaire (short form) in subgroups of the Hong Kong chinese population

“…Several routine instruments are available to measure physical activity, including self-report questionnaires, indirect calorimetry, direct observation, heart rate telemetry, and movement sensors [5]. All of these methods have well-known limitations [6], and for physical activity there is currently no perfect gold-standard criterion [7,8]. Movement sensors such as accelerometers have grown in popularity recently as a measure of physical activity [9], not only due to their objective measurements, but also due to their relatively small and unobtrusive size.…”